package com.lagou.edu.filter;

import com.lagou.edu.service.TokenServiceApi;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang.StringUtils;
import org.apache.dubbo.config.annotation.Reference;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.http.HttpCookie;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.stereotype.Component;
import org.springframework.util.CollectionUtils;
import org.springframework.util.MultiValueMap;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

import java.util.Arrays;
import java.util.List;

/**
 * 定义全局过滤器，会对所有路由生效
 */
@Slf4j
@Component  // 让容器扫描到，等同于注册了
public class AuthFilter implements GlobalFilter, Ordered {

    private static List<String> excludeUrls = Arrays.asList("/api/user/login/.*", "/api/user/register/.*", "/api/user/isRegistered/.*", "/api/code/create/.*");

    @Reference
    private TokenServiceApi tokenServiceApi;

    /**
     * 过滤器核心方法
     *
     * @param exchange 封装了request和response对象的上下文
     * @param chain    网关过滤器链（包含全局过滤器和单路由过滤器）
     * @return
     */
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        log.info("AuthFilter ------");
        ServerHttpRequest request = exchange.getRequest();
        ServerHttpResponse response = exchange.getResponse();
        String path = request.getPath().pathWithinApplication().value();
        for (String urlPattern : excludeUrls) {
            if (path.matches(urlPattern)) {
                return chain.filter(exchange);
            }
        }
        MultiValueMap<String, HttpCookie> cookies = request.getCookies();
        List<HttpCookie> oauthTokens = cookies.get("oauth_token");
        if (CollectionUtils.isEmpty(oauthTokens) || StringUtils.isBlank(oauthTokens.get(0).getValue())) {
            return handleReject(response);
        }
        String oauthToken = oauthTokens.get(0).getValue();
        String email = tokenServiceApi.info(oauthToken);
        if (StringUtils.isBlank(email)) {
            // 决绝访问，返回
            return handleReject(response);
        }

        // 合法请求，放行，执行后续的过滤器
        return chain.filter(exchange);
    }

    private Mono<Void> handleReject(ServerHttpResponse response) {
        response.setStatusCode(HttpStatus.UNAUTHORIZED); // 状态码
        String data = "Request be denied!";
        DataBuffer wrap = response.bufferFactory().wrap(data.getBytes());
        return response.writeWith(Mono.just(wrap));
    }


    /**
     * 返回值表示当前过滤器的顺序(优先级)，数值越小，优先级越高
     *
     * @return
     */
    @Override
    public int getOrder() {
        return 1;
    }
}
